Improvement in fluids for writing on checks, drafts



UNITED STATES ATENT FICE.

CHARLES L. LAWRENCE, OF NEW YORK, N. Y.

Specification forming part of Letters Patent No. 115,744, dated June 6, 1871.

To all whom it may concern:

Be it known that I, CHARLES L. LAWRENCE, of the city and State of New York, have invented an Improvement in Writing Material for Checks, Drafts, &o., and the following is declared to be a correct description thereof.

The object of this invention is to *prevent alteration in checks, drafts, bonds, or other evidences of debt, by means of an ink that removes the color from tinted paper at the portionwritten overfs'o that names, numbers, signatures, or amounts written in this writing material cannot be changed, because the fabric of the paper itself is deprived of its tinting color. This writing material is made by dissolving about one pound of carbonate of potash in a gallon of hot water, and then adding about twelve ounces of slaked lime, and boiling and removing any scum, and then allowing the material to cool and the impurities to subside, after which the clear liquid is drawn 011' with a. siphon.

Coloring matter, such as tincture of cardamine, may be employed to tinge this compound and give it the appearance of an ink.

When this'material is employed for writing, the alkali of the same penetrates the tinted paper and deprives it of color, especially when the paper is tinted of a rather heavy blue color.

This material may also be used with a paper tinted green, and the writing appears of a white, or nearly White, color, and is very reliable for any writin g that requires to be of a character that is diflicult to alter.

I do not lay claim to a caustic alkali, as I am aware that the same is prepared with lime and an alkali but my invention is a new article of manufacture consisting of a writing material of proper strength for tinted paper, put up in bottles similarly to an ink, and used for the purposes aforesaid.

I claim as my invention The writing material, prepared as aforesaid, and bottled for use as an ink upon tinted paper, as set forth.

Signed by me this 6th day of March, 1871.

CHARLES L. LAWRENCE.

Witnesses:

CHAS. E. SMITH, GEO. l. PINCKNEY. 

